Spacer device for a basket forming apparatus

ABSTRACT

A spacer device for use with a basket forming apparatus, the spacer device comprises a plurality of angularly spaced, radially extending arms ( 3, 4, 5, 6 ) corresponding in number to the number of metal bars forming the basket, each of which arms is adapted in use to engage with a respective one of the metal bars forming the basket-shaped article as the said article is twisted into its finished shape.

The present invention relates to a spacer device for use with apparatusfor forming from a plurality of metal bars secured together at each enda twisted and enlarged basket of bulbous shape, as illustrated in FIG. 1of the accompanying drawings. These basket-shaped articles are commonlyused as decorative features in wrought iron designs.

It is known to form decorative baskets from a plurality of metal barsusing both manually operated and electro-hydraulic machines. A manuallyoperated apparatus for forming baskets from metal bars is disclosed inPCT/GB96/02817. In general terms the operating procedure for bothmachines is the same. Firstly, a group of straight, square section metalbars, typically four in number, with the ends secured together issecured at each end between a fixed gripper ring or clamp and arotatable gripper ring or clamp of the machine. The bars are thentwisted on the machine through 360 degrees in one direction causing thebars to assume the shape and configuration shown in FIG. 2 of theaccompanying drawings. The bars are then twisted in the reversedirection through 720 degrees whilst at the same time the distancebetween the fixed and the rotatable clamps is shortened to exert acompressive force on the bars. This is illustrated in FIG. 3 of theaccompanying drawings. The result is generally that each steel bar inthe now formed basket has, by virtue of its initial twist, lost itsability to resist a compressive force and so when twisted in the reversedirection and compressed buckles outwardly to assume the requiredbulbous shape. Each of the bars in the group is subject to neardestructive twisting, particularly in the regions (a) thereof where thebars enter the clamps. In metallurgical terms this weakens the bars atthese points.

For ease of availability and for cost considerations general quality hotrolled mild steel is the material of choice for the metal bars fromwhich decorative baskets are formed. However, the manufacturingtolerances of this material are so wide that even along a single lengthof 6 meter stock bar its size, cross-section and strength can varygreatly. These variations can give rise to inconsistencies in the shapeof the formed baskets. In particular, the size of the gap between eachadjacent pairs of bars can be irregular. This problem can be overcome byusing metal bar of high quality and close dimensional tolerances.However, the cost of such bar makes the finished product prohibitivelyexpensive.

It is an object of the present invention to provide a spacer device foruse with a basket forming apparatus which ensures regular spacingbetween the metal bars forming the basket, thus obviating the need toemploy quality close tolerance steel.

According to the present invention there is provided a spacer device foruse with a basket forming apparatus, the spacer device comprising aplurality of angularly spaced, radially extending arms corresponding innumber to the number of metal bars forming the basket, each of whicharms is adapted in use to engage with a respective one of the metal barsforming the basket-shaped article as the said article is twisted intoits finished shape.

In use the spacer device according to the present invention is placed inposition on the unfinished basket-shaped article immediately prior tountwisting the article through the last few degrees of rotation. As thearticle is twisted through these last few degrees of rotation each ofthe metal bars engages with a respective one of the arms of the spacerdevice, thus ensuring that the gap between adjacent pairs of metal barsis limited to the angular distance between the arms against which theyengage.

In a preferred embodiment of the present invention the bars forming thespacer device are equi-angularly spaced, thus ensuring that all of themetal bars forming the basket-shaped article are equi-distantly spaced.

To ensure that the spacer device is retained in position on theunfinished basket-shaped article at least one of the said radiallyextending arms may comprise a hook at its free end which hooks over oneof the metal bars forming the basket-shaped article.

In one embodiment of the present invention each of the said arms extendsradially outwardly from a central hub.

In an alternative embodiment of the present invention each of the saidarms extends radially inwardly from an annular support or collar theinternal diameter of which is greater than the maximum outer diameter ofthe basket-shaped article. In this alternative embodiment each of thesaid arms is at least partially retractable relative to the collarthereby facilitating placement of the spacer device on the article andengagement of the arms in the gaps between adjacent pairs of metal bars.The arms can also be retracted to facilitate removal of the spacerdevice from the finished article.

The retractable arms may be moved in and out of their working positionssimultaneously by means of an automatic drive system. Alternatively,each arm may be moved manually between its extended and retractedpositions. In this later case each arm is preferably connected to aspring which biases it towards its extended position and locking meansfor engaging the arm against the spring bias in its retracted position.

Embodiments of the present invention will now be described, by way ofexample, with reference to the accompanying drawings, in which:

FIG. 1 shows a typical basket-shaped article formed from a cluster offour metal bars;

FIG. 2 shows the first stage in the manufacture of the basket-shapedarticle shown in FIG. 1:

FIG. 3 shows the second stage in the manufacture of the basket-shapedarticle shown in FIG. 1;

FIG. 4 shows one embodiment of a spacer device according to the presentinvention for use in the manufacture of basket-shaped article formedfrom four metal bars;

FIG. 5 shows the spacer device of FIG. 4 mounted in position between thebars of a basket-shaped article which is in the second stage ofmanufacture;

FIG. 6 shows a second embodiment of a spacer device according to thepresent invention for use in the manufacture of basket-shaped articlesformed from eight metal bars;

FIGS. 7, 8 and 9 illustrate how the spacer device shown in FIG. 6 isemployed during the manufacture of a basket-shaped article.

Referring to FIG. 4 of the accompanying drawings there is shown anembodiment of a spacer device in accordance with the present inventionfor use with the most common of basket designs where four square barsare welded together and subjected to the predetermined twisting andcompressing actions as described earlier. The spacer device is comprisedof two parts 1 and 2 which are adapted to be connected together to forma cross of four radially extending arms 3 to 6, equidistantly spacedfrom each other by 90 degrees. The two parts 1 and 2 are simplyconnected together by inserting arm 3 of part 1 into a through hole inthe central body 7 of part 2. A hook 8 is provided at the free end ofarm 4 to enable the spacer device to be secured in position to one ofthe metal bars forming a basket-shaped article as can be seen in FIG. 5.

The spacer device fits easily into the inner void of the basket-shapedarticle just before its formation is complete at a state of theuntwisting where the gap between each adjacent pair of metal bars isgreater than the diameter of the arms 3 to 6 forming the spacer device.At this stage of introducing the spacer device into the basket it mustbe appreciated that the metal bars that constitute the structure of thebasket-shaped article have undergone considerable torsional disruptionsuch that they each, for the reasons mentioned hereinabove, respondedslightly differently to each other in the total process and this usuallyresults in the gaps varying.

Having introduced the spacer device into the inner void of thebasket-shaped article and hooked the hook 8 over one of the metal barsthereof the final few degrees of rotation can now be executed. As it iseach metal bar forming the article engages against a respective one ofthe arms 3, 5 and 6, with the fourth metal bar being engaged by the hook8 on the end of arm 4. This ensures that the gap between each adjacentpair of metal bars is equal to the angular distance between eachadjacent pair of arms 3 to 6. Once satisfied with the result, the spacerdevice can be easily removed from the inner void of the basket-shapedarticle by withdrawing part 1 from part 2.

It will be appreciated that the spacer device can be used onbasket-shaped articles during their manufacture. It can also be used torectify basket-shaped articles which have been malformed in previousoperations, thus avoiding the need to scrap them. This is simply done byplacing the basket back into the twisting machine and slightlyuntwisting it to a point where the gaps between all bars are just wideenough to accept the arms. After introducing the spacer device into thebasket void, the basket-shaped article can be finally twisted through afew degrees to the point where all metal bars touch the spacer arms thusproducing a perfect shape.

The design of the spacer device is such that upon completion of thebasket-shaped article the spacer arms can be easily removed withoutcausing any disruption to it.

Where it is required to produce a basket-shaped article comprising eightmetal bars instead of four, two of the spacer devices shown in FIG. 4may be used together with one of the two offset from the other by anangle of 45 degrees.

Referring now to FIG. 6 there is shown an alternative embodiment of aspacer device according to the present invention. The spacer devicecomprises a circular collar 21 which is greater in diameter than themaximum diameter of the basket-shaped article on which it will be used.As shown, eight round equiangularly spaced arms 22 are supported inguide holes in the collar 21. This eight armed spacer device can be usedon basket-shaped articles with either four or eight metal bars. However,if it is only to be used on articles with four metal bars four of thespacer arms 22 can be dispensed with.

Between each arm 22 and the collar 21 is a spring 23 which causes thearm 22 to be biased inwardly towards the center of the collar 21. Aguide pin 24 engages through the collar 21 into a slot 25 in each arm22. Towards the inner end of each arm 22 the slot 25 turns back onitself for a small distance. By retracting an arm 22 back against thespring 23 and then twisting it the guide pin 24 can be engaged in thisturned back part of the slot 25 to hold and retain the arm in a retractposition against the spring 23. A knob 26 is provided at the outer endof each arm to facilitate pulling it back and twisting it. This enablesthe spacer device to be positioned for use on a basket-shaped article.It also facilitates removal of the spacer device after use.

In use the spacer device shown in FIG. 6 operates in exactly the sameway as the one shown in FIG. 4.

Although the spacer device described with reference to FIG. 6 ismanually operated it will be understood that it can be adapted forautomatic operation. In particular each of the retractable arms may beconnected to drive system which causes them all to be extended andwithdrawn relative to the collar simultaneously.

What is claimed is:
 1. A spacer device for use with a basket formingapparatus which comprises a twisting machine for twisting a number ofmetal bars into a basket-shaped article, the spacer device comprising aplurality of angularly spaced, radially extending arms (3, 4, 5, 6)corresponding in number to the number of metal bars forming the basketand fixed in a select angular relationship with respect to each other,each of which arms is adapted in use to engage with a respective one ofthe metal bars forming the basket-shaped article as said article istwisted into its finished shape within the basket forming apparatus. 2.A spacer device according to claim 1, wherein the bars forming thespacer device are equi-angularly spaced.
 3. A spacer device according toclaim 1, wherein at least one of the said radially extending arms (3, 4,5, 6) comprises attachment means whereby the arm can be attached to oneof the metal bars forming the basket-shaped article to retain the spacerdevice in position.
 4. A spacer device according to claim 3, wherein theattachment means comprises a hook (8) which hooks over one of the metalbars forming the basket-shaped article.
 5. A spacer device according toclaim 1, wherein each of the said arms extends radially outwardly from acentral hub.
 6. A spacer device according to claims 1, wherein each ofthe said arms extends radially inwardly from an annular support orcollar the internal diameter of which is greater than the maximum outerdiameter of the basket-shaped article.
 7. A spacer device according toclaim 6, wherein each of the said arms is at least partially retractablerelative to the collar thereby facilitating placement of the spacerdevice over the unshaped metal bars and engagement of the arms in thegaps between adjacent pairs thereof, and of the spacer device from thefinished basket-shaped article.
 8. A spacer device according to claim 7,wherein the retractable arms are moved in and out of their workingpositions simultaneously by means of an automatic drive system.
 9. Aspacer device according to claim 7, wherein each of the arms is movedmanually between its extended and retracted positions.
 10. A spacerdevice according to claim 9, wherein each arm is connected to a springwhich biases it towards its extended position and locking means forengaging the arm against the spring bias in its retracted position.